Muscular System Flashcards
List 3 Functions of the muscular system
Movement - result of muscular contraction
Movement of substances
Storage of Substances such as Oxygen and Glycogen
Maintaining posture and balance through continued partial muscle contraction.
Heat production - Thermogenesis
Give 5 example of movement of substances in muscles in the body.
Heart - muscle pumps blood around the body
Sphincters prevent out flow from hollow organs
Smooth muscle in blood vessel walls helps control blood flow
Smooth muscle moves food through the digestive tract and urine through the urinary system.
Diaphragm draws air into airways/lungs
What is Thermogenesis
Heat production is also known as Thermogenesis. It helps maintain normal body temperature. Shivering describes involuntary contractions of skeletal muscle.
What are the 4 muscle properties
Contractility - ability to contract (shorten)
Excitability - ability to conduct an electrical current. Nerve impulses cause muscle to contract.
Extensibility - ability for muscle to stretch without being damaged.
Elasticity - ability to return to original length and shape after contraction or extension gives it spring
Name 2 muscles that are striated
Cardiac Muscle and Skeletal muscle
What are the differences in striated and non striated muscles.
Striated muscles contain cells aligned in parallel bundles that form stripes visible with a microscope.
Non striated muscle contain cells that are randomly arranged with no stripes visible under the microscope
What muscle is non striated
Smooth muscle
What are the key features of Skeletal muscle
Striated - attaches between bones and creates movement at joints.
Voluntary muscle
What are the key features of Cardiac muscle
Striated - forms the heart muscle
Involuntary muscle that generates its own rhythmic contraction. (autorhythmic)
What are the key features of Smooth muscle
Non Striated - found in the walls of blood vessels, walls of the gut and in the iris.
Involuntary muscle
What is the purpose of striated muscle
Gives us a very uniform contraction, you get the same contraction each time. It is able to do this because of the way it is aligned in bundles.
The heart muscle is arranged similar to a tree with a branching process. Why is this?
So it can gradually spread a wave of contraction around the heart in a very uniform way.
How many skeletal muscles in the body
640
What percentage of body weight does skeletal muscle account for?
40%
What is skeletal muscle covered by what is it and what does it do?
Covered by fascia which is a dense connective tissue that organises muscle, secures it to skin and provides stability.
What is a major component of Fascia
Collagen
What is the cell membrane of skeletal muscle fibres called
Sarcolemma
Cytoplasm in the muscle cell is called
Sarcoplasm
What is the function of transverse tubules in the cell
extend from the cell membrane into the muscle cells.
Where is calcium stored in muscle and why do we need calcium.
It is stored in the sarcoplasmic reticulum and it is needed for muscle contraction
What is myoglobin and what is its the function
Iron and Oxygen binding protein stores oxygen in muscles and makes the muscle appear red.
What is the function of transverse tubules
They ensure that electrical impulses travelling along the muscle gets to the inside of the cell.
Why do Cardiac and Skeletal muscle contain lots of Mitochondria and where are they located
for aerobic respiration - cardiac and skeletal muscle are metabolically active. They are located close to myoglobin
Why do skeletal cells contain many nuclei
Muscle cells/fibres are formed from the fusion of cells called myoblasts in the embryo.
Can muscle cells under go mitosis
No
How would muscle cells regenerate
They have limited regenerative capacity by using satellite cells. The number of skeletal muscle fibres each person has is set at birth.
Describe the cardiac Muscle
Striated forms the heart muscle. Involuntary muscle that generates its own rhythm on contraction.
Describe Skeletal Muscle
Striated - attaches between bones and creates movement at joints. Voluntary muscles.
Describe Smooth Muscle
Non striated - found in the walls of blood vessels walls of the gut and iris. It is an involuntary muscle
Explain the role of fascia
coating for skeletal muscles, it organises the muscle, secures it to the skin and provides stability. Collagen is a major component.
Why are we born with a set number of skeletal cells
Because muscle cell fibres are unable to undergo mitosis. They can only be made by the fusion of myoblasts attained prior to birth.
Define Myofibrils
Cylindrical structures formed of bundles of protein filaments within the muscle fibre. They are contractile threads arranged in striated pattern.
Describe TWO Myofilaments which make up myofibrils
Actin - thin filaments
Myosin - thick filaments shaped like a golf clubs; the myosin heads can bind to Actin.
Explain what is meant by sarcomeres
A Sarcomere is the basic unit of striated muscle and contains the following Bands;
H Band - Myosin Only
A Band - dark area where actin and myosin overlap
I Band light area of actin only filaments
Z Disc filaments of actin that are arranged at 90 degree angles where they separate the sarcomeres.
Define the following in relation to connective tissue:
- Epimysium
- Perimysium
- Endomysium
Epimysium - the entire muscle is surrounded by epimysium which attaches it to the fascia and tendons.
Perimysium - bundles of between 10-100 muscle fibres are bound together to form fascicles which is then surrounded by the perimysium
Endomysium - Is the thin sheath that surrounds individual muscle fibres.
What is the function of collagen fibres in connective tissue.
assists to tightly intermingle with other structures for better transfer of force
Describe/Explain the skeletal muscle Hierarchy
Myocytes contain myofibrils that are made up of smaller myofilaments actin and myosin
Myocytes are bundled together to form fascicles which are surrounded by the perimysium
Fascicles accumulate together to form the entire muscle which is surrounded by the epimysium.
The epimysium provides an attachment for the muscle to the periosteum of the bone.
What is the Neuromuscular Junction (NMJ)
It is the meeting point (synapse) where the motor neurons meet a muscle fibre
In the NMJ which neurotransmitter is stored n the motor neuron synaptic bulb ending
Acetylcholine
Define synapse
Small gap between 2 structures e.g synaptic end bulb and muscle
With regards to the Neuro muscular junction - What influences the strength of a muscle contraction?
Depends on the number of motor neurons that are conducting and electrical pulse at one time, as well as the frequency of impulses.
What is the motor end plate
the location where motor neurons terminate in tiny pads on the muscle fibre.
Describe what specifically happens in sliding filament contraction
Hint - make sure you include correct minerals
- Nerve impulse will arrive at the NMJ
- The nerve impulse (action potential) spreads along the sarcolemma and Transverse Tubules into the muscle cells where is releases calcium (Ca2+) from storage in the sarcoplasmic reticulum.
- Calcium and ATP cause the myosin head to bind to the actin filament next to it. As the Actin and Myosin bind the movement causes the filaments to slide over each other therefore shortening the fibre.
Describe what specifically happens in sliding filament Relaxation
- Nerve stimulation stops (no nerve impulse)
- Using Magnesium and ATP, calcium is actively transported (pumped back) into storage, this breaks the actin and myosin bond
- Actin and Myosin slide back into starting positions, lengthening the fibre again (relaxation)
What does magnesium do to muscle fibres
makes them less excitable and prevents myosin binding with actin .
Name 4 minerals essential for effective muscle activity
Calcium, magnesium, Iron, Sodium & potassium
What is the function of Sodium and potassium in muscle activity
allow the nerve impulse to arrive at the NMJ
Why do we need iron for muscle activity
Iron carries Oxygen around the blood to muscles to use to create energy.
List 3 hormones that promote Hypertrophy
Growth Hormone
Testosterone
Thyroid Hormone
Why is protein required to support hypertrophy during strength training?
During strength training, individuals experience high levels of muscle tissue breakdown and hence protein is required to support Hypertrophy
Why do muscles require higher levels of ATP
because they are highly energy demanding.
Describe the difference between aerobic and anaerobic respiration.
Aerobic respiration - requires oxygen to generate ATP
Requires a continual blood supply.
It occurs in the Mitochondria
Each reaction produces 38 ATP molecules (36 net) using only 2 molecules up in the reaction.
Anerobic respiration - produces ATP in the absence of Oxygen
Takes place in the cytoplasm and occurs via glycolysis. The reaction produces a net of two ATP Molecules
Produces lactic acid
What does lactic acid do
Lowers muscle PH and causes muscle fatigue
What is the equation for Anerobic respiration
Glucose > Lactic acid + energy
What is the equation for Aerobic respiration
Oxygen + (glucose) > carbon dioxide + water + energy
What does ATP Stand for
Adenosine triphosphate
Which type of respiration generates more ATP
Aerobic
Which type of activity is more suitable with anaerobic respiration
intensive short term activity
Why can anaerobic respiration lead to muscle fatigue
Due to the build up of lactic acid that lowers muscle PH
What are the 2 main pathways for ATP Synthesis
Aerobic respiration
Anaerobic respiration
What is Creatine Phosphate
Protein unique to muscles and is an energy storage form
Why is Creatine Phosphate important
When muscles cells are lacking ATP CP can provide a small but ready source of energy in the first 15 seconds of a contraction
Does a cell have more Creatine Phosphate or ATP
3 to 6 times more creatine phosphate
What is Creatinine
a by product from the break down of Creatine Phosphate
Complete Muscle fibres chart categorised as 3 types
On computer
What percentage of Slow Oxidative Fibres are there
50%
Which Face muscle opens the eyes
Orbicularis Oculi
which face muscle raises the eyebrow
Occipitofrontalis
What face muscle closes/pouts lips
Orbicularis Oris
What muscles of the face are used for Mastication
Masseter
Temporalis
which muscle turns and tilts head
Sternocleidomastoid
What muscle pulls head backwards and elevates (shrugs) and retracts shoulders.
Trapezius
Function of supraspinatus (one of rotator cuff muscles)
Initial 15% abduction of shoulder
Function of the Psoas and where does it run
Anterior to the lumbar spine) Runs from lower back through hip and attaches to the femur.
Function - Hip flexor (pulls thigh towards the trunk)
Function of the Latissimus Dorsi
Widest part of the back.
Function Extends, adducts and internally rotates arms
Function of the Quadratus Lumborum and where do we find it.
Sits between the top of the pelvis and 12th rib and is attached to 4 of the 5 lumbar spine.
Function - bending backwards or sideways vertebral extension or lateral flexion
What is the function of the Erector Spinae
Extension of the vertebral column. Keeps spine upright.
Which back muscle is commonly responsible for muscle aches
Erector Spinae
